4DSP Products Technical support

Dear Sir,

We see the FMC168 User Manual the external VCO is 1.25G and it seems the fixed Oscillator.

Is it possible to adjust the internal sampling clock to 80Mhz? (*external clock is 10 MHz reference clock now)

If it is impossible ,can we enable the internal VCO?

Best Regards,

Paul

Dear Sir:

This is the demand from one of our customer. (for FMC168-2-1-1-1)

The customer wants to use 80MHz as thier sampling clock. with a 10MHz external reference clock.

Can customer do this with a software seting in reference design? (please help to explain how to)

Or does it need to have a hardware change for the on-board VCO?

Thanks!

Neil

Hi,

that is correct the internal VCO is 1.25GHz and the PLL can only divide down to an integer multiple of this frequency.

To be able to use the FMC168 with the internal VCO of the PLL device requires a hardware modification and can be specified as a custom ordering option at the time of purchase.

It is also possible to use an 80Mhz external clock directly.

Best regards,

Erik

Hi Eric,

We want to use 80MHz as sampling clock with a 10MHz external reference clock.

If we used the internal VCO , Is it possible to adjust the internal sampling clock to 80Mhz?

Or we need to change the external VCO.

Best Regards,

Paul

Hi Paul

with the internal VCO of the onboard PLL this will be possible yes. You would have to discuss your requirements with sales in order to get the custom ordering option.

Best regards,

Erik